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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Smart Bird Feeder : Self-propelled and interactive / Smart fågelmatare : Självgående och interaktiv

Tegbrant, Daniel, Falkman, Edvin January 2022 (has links)
Bird feeding is somthing most are familiar with, either when children are feeding the swans or adults using some type of bird feeder in the garden. This project took that as inspiration to create something that automatically feed the birds while also monitoring them by capturing a picture and sending out this information as a teet on Twitter. This thesis examined if it was possible to connect different components relatively simple in order to create something more advanced. Research of the components was the first step in order to ensure the ability to create such a product. The following components were used, a Raspberry Pi 3 b+, Raspberry Pi camera module, IKEA PIR sensor, zigbee USB dongel, ultrasonic sensor and a micro servo motor. These components were connected to the Raspberry Pi and tested individually to ensure quality and function. When successfully tested, implementing them together was done and later construction of the mounting brackets and housing was made. Testing was done and results were finalized. This showed that all of our research questions were successfully answered with positive results and further research around implementing AI and weather protection would be usefully to successfully make this a fully functioning product. / Fågelmatning är något de flesta de flesta känner till, antingen när barn matar svanar eller vuxna som har en fågelmatare i trädgården. Det här projektet tog det som inspiration för att skapa något som automatiskt matar fåglar samtidigt som den övervakar funktionen genom att ta kort och skicka denna information som en tweet på Twitter. Den här avhandlingen undersökte om det var möjligt att sammankoppla olika komponenter relativt enkelt för att skapa något mer avancerat. Forskning om komponenterna var det första steget i att undersöka om detta var möjligt. Följande komponenter kom att användas, an Raspberry Pi 3 b+, Raspberry Pi kameramodul, IKEA PIRsensor, zigbee USBdongel, ultraljudsensor och en micro servomotor. Dessa komponenter kopplades in i Raspberry Pi:en och testades individuellt för att säkerhetställa kvalite och funktion. När testerna var lyckade implementerades de tillsammans och konstruktionen av fästen och ytterhölje fördigställdes. Tester gjordes och resultat sammanställdes. Dessa visade att alla våra forskningsfrågor blev besvarade med ett positivt resultat och framtida forskning kring implementeringen av AI och väderskydd är något som skulle kunna möjliggöra detta att bli en fullt fuktionerande produkt.
22

Transcript Abundance of Photorhabdus Insect-Related (Pir) Toxin in Manduca sexta and Galleria mellonella Infections

Castagnola, Anaïs, Mulley, Geraldine, Davis, Nathaniel, Waterfield, Nicholas, Stock, S. 29 September 2016 (has links)
In this study, we assessed pirAB toxin transcription in Photorhabdus luminescens laumondii (strain TT01) (Enterobacteriaceae) by comparing mRNA abundance under in vivo and in vitro conditions. In vivo assays considered both natural and forced infections with two lepidopteran hosts: Galleria mellonella and Manduca sexta. Three portals of entry were utilized for the forced infection assays: (a) integument; (b) the digestive route (via mouth and anus); and (c) the tracheal route (via spiracles). We also assessed plu4093-2 transcription during the course of a natural infection; this is when the bacteria are delivered by Heterorhabditis bacteriophora nematodes. Transcript abundance in G. mellonella was higher than in M. sexta at two of the observed time points: 15 and 18 h. Expression of pirAB plu4093-2 reached above endogenous control levels at 22 h in G. mellonella but not in M. sexta. Overall, pirAB plu4093-2 transcripts were not as highly expressed in M. sexta as in G. mellonella, from 15 to 22 h. This is the first study to directly compare pirAB plu4093-2 toxin transcript production considering different portals of entry.
23

Private Information Retrieval in an Anonymous Peer-to-Peer Environment

Miceli, Michael 20 May 2011 (has links)
Private Information Retrieval (PIR) protocols enable a client to access data from a server without revealing what data was accessed. The study of Computational Private Information Retrieval (CPIR) protocols, an area of PIR protocols focusing on computational security, has been a recently reinvigorated area of focus in the study of cryptography. However, CPIR protocols still have not been utilized in any practical applications. The aim of this thesis is to determine whether the Melchor Gaborit CPIR protocol can be successfully utilized in a practical manner in an anonymous peer-to-peer environment.
24

Estudo de planejamento integrado de recursos (PIR) para o sistema elétrico da Nicarágua: período 2013-2030 / Integrated Resource Plan (IRP) for the Nicaraguan electric system. 2013-2030

González, Carlos Germán Meza 24 February 2014 (has links)
O objetivo geral desta dissertação é aplicar a metodologia de Planejamento Integrado de Recursos para o sistema elétrico da Nicarágua, analisando o período entre 2013-2030. Na primeira parte, são apresentadas características do sistema elétrico e a necessidade da aplicação do PIR. Na segunda parte, são avaliados três programas de eficiência energética em andamento: substituição de dois milhões de lâmpadas incandescentes por fluorescente compacta, substituição de lâmpadas de vapor de mercúrio por vapor de sódio na iluminação pública e substituição de 20.000 lâmpadas T12 por T8 e T5 no setor público. Cada um desses programas foi avaliado em comparação com o uso da tecnologia LED disponível. Além disso, foram avaliadas as opções de oferta, empregando curvas de seleção e a curva de duração de carga. Foi incluída uma avaliação de sistemas fotovoltaicos ligados à rede, para o setor residencial, como opção de geração distribuída. Finalmente, os programas de eficiência energética são integrados com as ofertas de geração através de índices como o Fator de Carga da Conservação (FCC). / The main objective of this dissertation is to apply the methodology of Integrated Resource Planning (IRP) for the electric system of Nicaragua. Period 2013-2030. In the first part, some characteristics of the electrical system and the need for implementation of IRP are presented. In the second part, 3 ongoing energy efficiency programs are assessed: replacing of 2 million incandescent bulbs with Compact Fluorescent Lamps, mercury vapor lamps by sodium vapor lamps for street lighting and replacing 20,000 T12 lamps with T8 and T5 in the public sector. Each of these programs was evaluated by comparing with the available LED technology. Moreover, the supply options were evaluated using screening curves and the load duration curve. An evaluation of PV grid connected systems for residential sector was included. Finally, energy efficiency programs are integrated with supply options trough merit figures as the Conservation Load Factor (CLF).
25

Estudo comparativo entre a pir?lise do polietileno de baixa densidade, utilizando vermiculita modificada e SBA-15

Bezerra, Franciel Aureliano 20 January 2014 (has links)
Made available in DSpace on 2014-12-17T15:42:13Z (GMT). No. of bitstreams: 1 FrancielAB_DISSERT.pdf: 3637529 bytes, checksum: 50d6de8b3a00a0b045a5b17d540f59d2 (MD5) Previous issue date: 2014-01-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Catalytic processes are widely present in everyday life. This results in large number of studies seeking materials that may combine the low cost catalytic efficiency. Based on this assumption, the clays have long been used as catalysts, with its huge availability, diversity and possibility of improving their properties from structural changes, primarily responsible for this great use. Among the natural clays, vermiculite due to their characteristic properties (high cation exchange capacity and expansion), is suitable for various applications including as catalysts and catalyst supports. In this work, the acid leaching of clay vermiculite was performed, coming from Santa Luzia-PB, with nitric acid (2, 3 and 4 mol / L) and subsequent calcination of the materials obtained. The materials were named as Vx/400, where x is the acid concentration employed and 400 used in calcination temperature. The effectiveness of changes made was determined by XRD techniques, FT-IR, EDS, TG/DTG, nitrogen physisorption and DTP of n-butylamine. Acid leaching has improved some properties of the clay - specific area and acidity - but the control of the acid concentration used is of vital importance, since the highest concentration caused the partial destruction of vermiculite entailing a decline in their properties. For analysis of the catalytic activity of the modified clay was made a comparative study with the SBA -15 mesoporous materials, synthesized via hydrothermal method, using the pyrolysis of low density polyethylene (LDPE). The results showed that the acid plays a fundamental role in the conversion of the polymer into smaller molecules, the material V3/400 was more selective for the source monomer (ethylene) due to their increased acidity, which promotes more breaks bonds in the polymeric chain, while materials and V0/400 V2/400, lower acidity, showed higher selectivity to light hydrocarbons, the range of fuel (41.96 and 41.23%, respectively), due to less breakage and secondary condensation reactions chains; already V4/400 SBA-15/550 and resulted in lower percentages of light hydrocarbons and the partial destruction of the structure and low acidity, respectively, responsible for the inefficiency of materials / Os processos catal?ticos est?o largamente presentes no cotidiano. Isso resulta no grande n?mero de pesquisas buscando materiais que possam aliar baixo custo ? efici?ncia catal?tica. Partindo desse pressuposto, as argilas t?m sido muito utilizadas como catalisadores, sendo sua grande disponibilidade, diversidade e possibilidade de melhoria de suas propriedades, a partir de modifica??es estruturais, os principais respons?veis por esse grande uso. Entre as argilas naturais, a vermiculita devido ?s suas propriedades caracter?sticas (alta capacidade de troca cati?nica e de expans?o), ? apta para diversas aplica??es, entre elas, como suportes catal?ticos e catalisadores. Neste trabalho, foi realizada a lixivia??o ?cida da argila vermiculita, oriunda de Santa Luzia-PB, com ?cido n?trico (2, 3 e 4 mol/L) e posterior calcina??o dos materiais obtidos. Os materiais foram nomeados como Vx/400, onde x corresponde ? concentra??o ?cida empregada e 400 ? temperatura usada na calcina??o. A efici?ncia das modifica??es realizadas foi determinada pelas t?cnicas de DRX, FT-IR, EDS, TG/DTG, fisissor??o de nitrog?nio e DTP de n-butilamina. A lixivia??o ?cida melhorou algumas propriedades da argila ?rea espec?fica e acidez , por?m o controle da concentra??o ?cida empregada ? de vital import?ncia, visto que a maior concentra??o provocou a destrui??o parcial da vermiculita, acarretando em um decr?scimo das suas propriedades. Para an?lise da atividade catal?tica das argilas modificadas fez-se um estudo comparativo com o material mesoporoso SBA-15, sintetizado via m?todo hidrot?rmico, empregando-os na pir?lise de polietileno de baixa densidade (PEBD). Os resultados mostraram que a acidez exerce papel fundamental na convers?o do pol?mero em mol?culas menores; o material V3/400 foi o mais seletivo para o mon?mero de origem (eteno), devido ? sua maior acidez, que promove mais cis?es nas liga??es da cadeia polim?rica; enquanto os materiais V0/400 e V2/400, de menor acidez, apresentaram maior seletividade para hidrocarbonetos leves, da faixa dos combust?veis (41,96 e 41,23%, respectivamente), em virtude de menos cis?es e rea??es secund?rias de condensa??o nas cadeias; j? V4/400 e SBA-15/550 resultaram nos menores percentuais de hidrocarbonetos leves, sendo a destrui??o parcial da estrutura e baixa acidez, respectivamente, respons?veis pela inefici?ncia dos materiais
26

Estudo de planejamento integrado de recursos (PIR) para o sistema elétrico da Nicarágua: período 2013-2030 / Integrated Resource Plan (IRP) for the Nicaraguan electric system. 2013-2030

Carlos Germán Meza González 24 February 2014 (has links)
O objetivo geral desta dissertação é aplicar a metodologia de Planejamento Integrado de Recursos para o sistema elétrico da Nicarágua, analisando o período entre 2013-2030. Na primeira parte, são apresentadas características do sistema elétrico e a necessidade da aplicação do PIR. Na segunda parte, são avaliados três programas de eficiência energética em andamento: substituição de dois milhões de lâmpadas incandescentes por fluorescente compacta, substituição de lâmpadas de vapor de mercúrio por vapor de sódio na iluminação pública e substituição de 20.000 lâmpadas T12 por T8 e T5 no setor público. Cada um desses programas foi avaliado em comparação com o uso da tecnologia LED disponível. Além disso, foram avaliadas as opções de oferta, empregando curvas de seleção e a curva de duração de carga. Foi incluída uma avaliação de sistemas fotovoltaicos ligados à rede, para o setor residencial, como opção de geração distribuída. Finalmente, os programas de eficiência energética são integrados com as ofertas de geração através de índices como o Fator de Carga da Conservação (FCC). / The main objective of this dissertation is to apply the methodology of Integrated Resource Planning (IRP) for the electric system of Nicaragua. Period 2013-2030. In the first part, some characteristics of the electrical system and the need for implementation of IRP are presented. In the second part, 3 ongoing energy efficiency programs are assessed: replacing of 2 million incandescent bulbs with Compact Fluorescent Lamps, mercury vapor lamps by sodium vapor lamps for street lighting and replacing 20,000 T12 lamps with T8 and T5 in the public sector. Each of these programs was evaluated by comparing with the available LED technology. Moreover, the supply options were evaluated using screening curves and the load duration curve. An evaluation of PV grid connected systems for residential sector was included. Finally, energy efficiency programs are integrated with supply options trough merit figures as the Conservation Load Factor (CLF).
27

Sinteriza??o de matrizes cer?micas ? base de alumina refor?adas por carbetos a partir de precursores polim?ricos

Diniz, Marcus Alexandre 01 October 2007 (has links)
Made available in DSpace on 2014-12-17T14:07:24Z (GMT). No. of bitstreams: 1 MarcusAlexandreD.pdf: 2205651 bytes, checksum: 56cca2e578c0f1071a36ad849c8f80ca (MD5) Previous issue date: 2007-10-01 / Ceramic composites produced with polymerics precursors have been studied for many years, due to the facility of obtaining a complex shape, at low temperature and reduces cost. The main objective of this work is to study the process of sintering of composites of ceramic base consisting of Al2O3 and silicates, reinforced for NbC, through the technique of processing AFCOP, as well as the influence of the addition of LZSA, ICZ and Al as materials infiltration in the physical and mechanical properties of the ceramic composite. Were produced ceramic matrix composites based SiCxOy e Al2O3 reinforced with NbC, by hidrosilylation reaction between D4Vi and D1107 mixtured with Al2O3 as inert filler, Nb and Al as reactive filler. The specimens produced were pyrolised at 1200, 1250 and 1400?C and infiltred with Al, ICZ and LZSA, respectively. Density, porosity, flexural mechanical strength and fracture surface by scanning electron microscopy were evaluated. The microstructure of the composites was investigated by X-ray diffraction to identify the presence of crystalline phases. The composites presented apparent porosity varying of 31 up to 49% and mechanical flexural strength of 14 up to 34 MPa. The infiltration process improviment of the densification and reduction of the porosity, as well as increased the values of mechanical flexural strength. The obtained phases had been identified as being Al3Nb, NbSi2, Nb5S3, Nb3Si and NbC. The samples that were submitted the infiltration process presented a layer next surface with reduced pores number in relation to the total volume / Os comp?sitos cer?micos produzidos atrav?s de precursores polim?ricos v?m sendo estudados h? v?rios anos, tendo em vista a facilidade de moldagem em formas complexas, menores temperaturas de sinteriza??o e custo reduzido. O principal objetivo deste trabalho ? estudar o processo de sinteriza??o de comp?sitos de base cer?mica constitu?da de alumina e silicatos, refor?ados por carbetos de ni?bio, atrav?s da t?cnica de processamento AFCOP, bem como a influ?ncia da adi??o de LZSA, ICZ, e Al como materiais infiltrantes nas propriedades f?sicas e mec?nicas do comp?sito cer?mico. Foram produzidos comp?sitos de matriz cer?mica baseados em SiCxOy e Al2O3 refor?ados com carbeto de ni?bio, a partir da rea??o de hidrossila??o entre os olig?meros D4Vi (1,3,5,7 tetrametil 1,3,5,7 tetravinilciclotetrasiloxano) e D1107 Poli (metilhidrogeniosiloxano), misturados com alumina como carga inerte, ni?bio e alum?nio como aditivos reativos. As amostras produzidas foram pirolisadas a 1200?C, 1250?C e 1400?C e infiltradas com Al, ICZ e LZSA, respectivamente. Foram realizados ensaios de densidade, porosidade, resist?ncia mec?nica ? flex?o e an?lises da superf?cie de fratura por microscopia eletr?nica de varredura. A microestrutura dos comp?sitos foi investigada pela an?lise de difra??o de raios-x para identifica??o das fases cristalinas presentes. Os comp?sitos apresentaram porosidade aparente variando de 31 a 49 por cento e resist?ncia mec?nica ? flex?o de 14 a 34 MPa. Os resultados mostraram que o processo de infiltra??o promoveu uma melhoria na densifica??o e redu??o da porosidade, bem como um incremento nos valores de resist?ncia mec?nica do comp?sito. As fases formadas ap?s a pir?lise foram identificadas como sendo Al3Nb, NbSi2, Nb5Si3, Nb3Si e NbC. As amostras que foram submetidas ao processo de infiltra??o apresentaram uma camada superficial com reduzido n?mero de poros em rela??o ao volume total
28

Pir?lise t?rmica e catal?tica de res?duos de v?cuo gerados no refino de petr?leo

Lima, Regineide de Oliveira 17 February 2012 (has links)
Made available in DSpace on 2014-12-17T14:08:50Z (GMT). No. of bitstreams: 1 RegineideOL_DISSERT.pdf: 1906684 bytes, checksum: 6ab6bc4b30db454754e3cd6ba142d8d7 (MD5) Previous issue date: 2012-02-17 / In this study, was used a very promising technique called of pyrolysis, which can be used for obtaining products with higher added value. From oils and residues, since the contribution of heavier oils and residues has intensified to the world refining industry, due to the growing demand for fuel, for example, liquid hydrocarbons in the range of gasoline and diesel. The catalytic pyrolysis of vacuum residues was performed with the use of a mesoporous material belonging the M41S family, which was discovered in the early 90s by researchers Mobil Oil Corporation, allowing new perspectives in the field of catalysis. One of the most important members of this family is the MCM-41, which has a hexagonal arrangement of mesopores with pore diameters between 2 and 10 nm and a high specific surface area, making it very promising for use as a catalyst in petroleum refining for catalytic cracking, and their mesopores facilitate the access of large hydrocarbon molecules. The addition of aluminum in the structure of MCM-41 increases the acidity of the material, making it more positive for application in the petrochemical industry. The mesoporous material of the type Al-MCM41 (ratio Si / Al = 50) was synthesized by hydrothermal method starting from the silica gel, NaOH and distilled water added to the gel pseudobohemita synthesis. Driver was used as structural CTMABr. Removal of organic driver (CTMABr) was observed by TG / DTG and FTIR, but this material was characterized by XRD, which was observed the formation of the main peaks characteristic of mesoporous materials. The analysis of adsorption / desorption of nitrogen this material textural parameters were determined. The vacuum residues (VR's) that are products of the bottom of the vacuum distillation tower used in this study are different from oil fields (regions of Cear? and Rio de Janeiro). Previously characterized by various techniques such as FTIR, viscosity, density, SARA, elemental analysis and thermogravimetry, which was performed by thermal and catalytic degradation of vacuum residues. The effect of AlMCM-41 was satisfactory, since promoted a decrease in certain ranges of temperature required in the process of conversion of hydrocarbons, but also promoted a decrease in energy required in the process. Thus enabling lower costs related to energy expenditure from degradation during processing of the waste / No presente trabalho, foi utilizada uma t?cnica bastante promissora denominada de pir?lise, a qual pode ser usada para obten??o de produtos com maior valor agregado. Partindo de ?leos e res?duos, visto que a contribui??o desses petr?leos mais pesados e res?duos tem se intensificado para o mundo da ind?stria do refino, em virtude da crescente demanda por combust?veis, como por exemplo, hidrocarbonetos l?quidos na faixa de gasolina e ?leo diesel. Os res?duos de v?cuo (RV?S) que s?o produtos de fundo da torre de destila??o a v?cuo utilizados neste trabalho, foram provenientes de diferentes petr?leos (regi?es do Cear? e Rio de Janeiro). Estes res?duos foram previamente caracterizados por v?rias t?cnicas como: FTIR, viscosidade, densidade, SARA, an?lise elementar e termogravimetria, pela qual foi realizada a degrada??o t?rmica e catal?tica dos res?duos de v?cuo. A pir?lise catal?tica dos res?duos de v?cuo foi realizada com a utiliza??o de um material mesoporoso pertencente ? fam?lia M41S, que foi descoberto no in?cio dos anos 90 por pesquisadores da Mobil Oil Corporation, possibilitando assim novas perspectivas no ramo da cat?lise. Um dos mais importantes membros desta fam?lia ? o MCM-41, que possui um arranjo hexagonal de mesoporos com di?metros de poros entre 2 a 10 nm e uma alta ?rea espec?fica, tornando-o bastante promissor para ser utilizado como catalisador no refino do petr?leo para o craqueamento catal?tico, j? que seus mesoporos facilitam o acesso de mol?culas grandes de hidrocarbonetos. A incorpora??o do alum?nio na rede do material MCM-41 proporciona a acidez ao material, possibilitando sua aplica??o na ind?stria petroqu?mica. O material mesoporoso do tipo Al- MCM41 (raz?o Si/Al=50) foi sintetizado atrav?s do m?todo hidrot?rmico partindo da S?lica gel, NaOH e ?gua destilada, acrescentado de pseudobohemita no gel de s?ntese. O efeito do AlMCM-41 foi satisfat?rio, pois promoveu uma diminui??o de determinadas faixas de temperatura requeridas no processo de convers?es dos hidrocarbonetos, como tamb?m promoveu uma diminui??o na energia necess?ria do processo. Possibilitando assim, menos custos relacionados ao gasto de energia para a degrada??o durante o processamento desses res?duos. Como direcionador estrutural foi utilizado CTMABr. A remo??o do direcionador org?nico (CTMABr) foi verificado por TG/DTG e FTIR, como tamb?m este material foi caracterizado por DRX, o qual foi constatado a forma??o dos principais picos caracter?sticos dos materiais mesoporosos. Pela an?lise de adsor??o/dessor??o de nitrog?nio deste material foram determinados os par?metros texturais
29

Otimiza??o da s?ntese do AlSBA-15 para produ??o de biodiesel por transesteri-fica??o do ?leo de coco / Optimization of the synthesis of AlSBA-15 for production of biodiesel by transesterification of coconut oil

Rodrigues, Gic?lia 22 August 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-11-27T15:27:52Z No. of bitstreams: 1 GiceliaRodrigues_TESE.pdf: 4017865 bytes, checksum: c0fa528988ec3e75c837780c20f66c73 (MD5) / Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2015-11-30T23:51:12Z (GMT) No. of bitstreams: 1 GiceliaRodrigues_TESE.pdf: 4017865 bytes, checksum: c0fa528988ec3e75c837780c20f66c73 (MD5) / Made available in DSpace on 2015-11-30T23:51:12Z (GMT). No. of bitstreams: 1 GiceliaRodrigues_TESE.pdf: 4017865 bytes, checksum: c0fa528988ec3e75c837780c20f66c73 (MD5) Previous issue date: 2014-08-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Atualmente, o Brasil conta com grande potencial e boas perspectivas futuras para a manuten??o e amplia??o de sua matriz energ?tica. S?o exemplos de alternativas para o futuro, os petr?leos oriundos do pr?-sal, energias e?licas, hidrel?tricas, nuclear, al?m dos biocombust?veis. O est?mulo ? produ??o e ao consumo de bicombust?vel favorece mundialmente a pol?tica de preserva??o ao meio ambiente, contribuindo na redu??o dos gases, poluentes, causadores do efeito estufa e redu??o das altera??es clim?ticas. A presen?a de catalisadores nos processos de produ??o de bicombust?veis desempenha um importante papel na melhoria da rotas de produ??o, tais como: taxa de rea??o, rendimento e seletividade de produtos e co-produtos de alto valor agregado. A tend?ncia atual das pesquisas nesse campo foca no aprimoramento desses processos com o uso de catalisadores heterog?neos, visto que catalisadores heterog?neos apresentam vantagens significativas, tais como: menor contamina??o dos produtos, facilidade de separa??o do catalisador do meio reacional, possibilidade de reaproveitamento do catalisador, diminui??o dos problemas de corros?o. Portanto, pesquisas est?o sendo desenvolvidas para obten??o de materiais mesoporosos, que s?o catalisadores heterog?neos, devido ao fato de que esses materiais apresentam facilidade de s?ntese e s?o economicamente vi?veis, apresentam poros relativamente grandes que facilitam a acessibilidade de ?cidos graxos no interior das part?culas, minimizando resist?ncias ao transporte de massa. Ap?s montada matriz experimental para a s?ntese do Al-SBA-15, foi realizado a s?ntese hidrot?rmica do Al-SBA-15 com diferentes raz?es de Si/Al variando as quantidades estequiom?tricas dos materiais precursores.Os testes catal?ticos foram a rea??o de transesterifica??o utilizando como m?tria-prima o ?leo de coco bruto e a pir?lise. As rea??es de transesterifica??o foram realizadas em um reator Parr de a?o inoxid?vel, modelo 4523, equipado com agitador mec?nico, indicadores de temperatura e press?o. O tratamento cin?tico referente aos dados da pir?lise do ?leo de coco puro e do ?leo de coco com AlSBA-15, realizou-se por meio da utiliza??o de curvas termogravim?tricas (TG) obtidas em uma termobalan?a modelo TGA/SDT Q600 da TA instruments, nas seguintes taxas de aquecimento: 5,10 e 20?C min-1. O ?leo de coco bruto apresentou com uma mat?ria-prima apropriada para obten??o do biodiesel via rota et?lica e o catalisador sintetizado com as condi??es experimentais I, apresentou as melhores condi??es para a s?ntese de biodiesel. Os aspectos visuais e as caracter?sticas f?sico-qu?micas dos produtos da rea??o, mostram que o catalisador AlSBA-15 favoreceu a rea??o. De acordo com as analises f?sico-qu?micas a ordem de estabilidade oxidativa do produto da rea??o de transesterifica??o foi: 1500?C +AlSBA-15 > 100?C> 100?C + AlSBA-15> 200?C + AlSBA-15. / Stimulus encouraging the production and consumption of biodiesel favors the policy of pre-serving the environment, contributing to the reduction of greenhouse gas reducing climate change. The current trend of research in this field focuses on improving these processes with the use of heterogeneous catalysts, seeing has significant advantages such as: low contamination of products, ease of separation of the catalyst from the reaction medium, possibili-ty of reuse of the catalyst, decreased corrosion problems. The objective of this research was to optimize the synthesis of AlSBA-15 for the production of biodiesel through transesterification process via ethyl route. For the optimization of hydrothermal synthesis of type AlSBA-15 catalyst has assembled a 23 factorial experimental matrix with eleven trials. The stoichiometric amounts of starting materials were varied according to different ratios Si / Al which is a factor in the experimental design, in addition to the time and temperature of aging of the synthesis gel. The material showed the best results of characterization (SBET = 591.7 (m2 / g), Vp = 0.83 (cm3 / g), Dp = 5.59 (nm), w = 6.48 (nm) was synthesized at 100 ? C for 24 hours, with a ratio Si / Al = 10.This material was applied as a heterogeneous catalyst in the reaction of ethyl transesterification as raw coconut oil in natura. Coconut oil presented suitable for obtaining biodiesel via ethyl route.The visual aspects and physical-chemical characteristics of the reaction products show that AlSBA-15 catalyst favored the reaction. According to physical-chemical analysis the order of oxidative stability of the product of the transesterification reaction was: catalytic reaction at 1500 ? C> non-catalytic reaction at 100 ? C> 100 ? C catalytic> catalytic reaction at 200 ? C Reaction. The results of oxidative stability and kinematic viscosity shows that the biodiesel produced in the catalytic sandblasting held at 150 ? C which was maintained within the ABNT NBR 7148, ABNT NBR 10441 and EN 14112.
30

S?ntese e caracteriza??o de nanotubo de carbono derivado de lignina extra?da do mesocarpo do dend? (Elaeis guineensis)

Te?filo, Alessandra Luzirene Costa 10 July 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-12T13:28:17Z No. of bitstreams: 1 AlessandraLuzireneCostaTeofilo_DISSERT.pdf: 3632851 bytes, checksum: 9d450be349181a503633ee784e996b36 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-14T15:32:18Z (GMT) No. of bitstreams: 1 AlessandraLuzireneCostaTeofilo_DISSERT.pdf: 3632851 bytes, checksum: 9d450be349181a503633ee784e996b36 (MD5) / Made available in DSpace on 2018-03-14T15:32:18Z (GMT). No. of bitstreams: 1 AlessandraLuzireneCostaTeofilo_DISSERT.pdf: 3632851 bytes, checksum: 9d450be349181a503633ee784e996b36 (MD5) Previous issue date: 2017-07-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Com a descoberta dos nanotubos de carbono de parede simples (NTCPS) por Sumio Iijima, em 1991, os pesquisadores interessaram-se em sintetizar NTC em larga escala, com qualidade e baixo custo. Este trabalho prop?e uma nova metodologia e ecologicamente correta para a s?ntese de NTC por pir?lise da lignina extra?da do mesocarpo do dend? (Elaeis guineensis). Para a obten??o da amostra, a lignina foi pirolisada em um forno tubular a 1.000?C com uma determinada taxa de aquecimento 10?C/min e os experimentos foram realizados em diferentes intervalos de temperatura e sob fluxo de g?s arg?nio. Ap?s o processo de s?ntese, foi verificada a forma??o de nanomateriais de carbono. Os NTC?s foram submetidos a funcionaliza??o em solu??o (3:1) de ?cido sulf?rico (H2SO4) e ?cido n?trico (HNO3), sob agita??o, adicionado hidr?xido de am?nia (NH4OH) e lavado em seguida, neutralizado. Os nanotubos tamb?m foram funcionalizados com quitosana. O material final foi caracterizado a ?rea superficial, estrutural e propriedades f?sico-qu?micas, por meio de Difra??o de Raios X (DRX), An?lise T?rmica (TGA/DTA), Espectroscopia Raman, Microscopia Eletr?nica de Transmiss?o (MET), Espectroscopia na regi?o do Infravermelho com Transformada de Fourier com reflect?ncia difusa atenuada (FTIR/ATR) e Eletroan?lise do atrav?s de Voltametria C?clica e Imped?ncia. Os resultados demonstraram que o processo de pirolise sob fluxo de arg?nio obteve nanotubos com di?metros m?dios de 7 nm com potencial aplica??o. / With the discovery of Carbon single-wall nanotubes (SWNT?s) by Sumio Iijima in 1991, the researchers were interested in synthesizing CNT?s on a large scale, with quality and low cost. This work proposes a new methodology and ecologically correct for the synthesis of CNT?s by lignin pyrolysis extracted from the mesocarp of palm oil (Elaeis guineensis). To obtain the sample, the lignin was pyrolyzed in a tubular furnace 1.000?C with a given heating rate 10?C/min and the experiments were performed at different temperature ranges and under argon gas flow. After the synthesis process, the formation of carbon nanomaterials were verified. The CNT?s were subjected to functionalization in solution (3:1) of sulfuric acid (H2SO4) and nitric acid (HNO3) under stirring, added ammonia hydroxide (NH4OH) and washed, then neutralized. The nanotubes were also functionalized with chitosan. The final material was characterized by the surface area, structural and physical-chemical properties, using X-ray Diffraction (XRD), Thermal Analysis (TGA/DTA), Raman Spectroscopy, Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) Attenuated Total Reflection (ATR) spectroscopy and Electroanalysis through Cyclic Voltammetry and Impedance. The results showed that the pyrolysis process under argon flux obtained nanotubes with mean diameters of 7 nm with potential application. / 2018-10-10

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